PLATYCRINID^. — CARIOCRINUS. 57 



there may possibly be certain irregularities of form which we have not been fortunate 

 enough to discover. 



We are indebted to the obliging kindness of Mr. Lyell for the opportunity he lias 

 afforded us of examining and drawing the crinoids which he brought from America, 

 among which are the beautiful specimens of Cariocrinus represented in plate 1, with the 

 exception of figure 3, c, which is in the museum of the Bristol Institution. 



Though the American formations do not appear to be so rich in the variety of 

 crinoidal forms as the European, yet several specimens of great beauty have already 

 been developed, and when the geology of that fine country has been more extensively 

 examined by scientific explorers, we may hope to meet with many new kinds. All 

 those we have seen from America differ from any known European species, and the 

 genus Cariocrinus appears to be peculiar to the new continent. 



These remarks chiefly apply to the number of species, not to the paucity of 

 individuals, for some American strata, as exemplified by Mr. Lyell's specimens, are 

 almost wholly, as in some European rocks, composed of crinodial remains. 



